Tetrazol-5-yl 2-nitro-3-phenylbenzofurans and antimicrobial use thereof

ABSTRACT

Antimicrobial 2-nitro-3-phenylbenzofurans wherein the benzo or the 3-phenyl portion of the molecule is bonded to an alkylene or an oxyalkylene group which is in turn bonded to a basic nitrogen atom or to the nitrogen atom of an (N-lower alkanoyl)amino group.

REFERENCE TO RELATED APPLICATION

This is a continuation-in-part of copending application Ser. No. 973,150filed Dec. 26, 1978, abandoned.

BACKGROUND OF THE INVENTION

This invention relates to a class of 2-nitro-3-phenylbenzofurans whereinthe benzo or the 3-phenyl portion of the molecule is bonded to analkylene or an oxyalkylene group which is in turn bonded to a basicnitrogen atom or to the nitrogen atom of an (N-lower alkanoyl)aminogroup (which are active as antimicrobial agents) and processes for theiruse. The nitrogen atoms in the described substituents may be part ofunsubstituted amino groups, mono- or disubstituted amino groups orcyclic amines. The invention also relates to pharmaceutically acceptablesalts (e.g. acid halide and quaternary ammonium salts) of the basiccompounds of the invention, to the use of the compounds of the inventionas antimicrobial agents and to intermediates useful in their synthesis.

Compounds containing the 2-nitro-3-phenylbenzofuran nucleus are known.See, for example, U.S. Pat. Nos. 4,022,908; 4,048,323; 4,066,782;4,067,993 and 4,124,704. Compounds containing said nucleus which alsocontain a basic nitrogen-containing group or an (N-lower alkanoyl)aminogroup are not known, however. More specifically, compounds wherein thearomatic benzo or 3-phenyl portions of the 2-nitro-3-phenylbenzofurannucleus is bonded to an alkylene or oxyalkylene group which is in turnbonded to a basic nitrogen atom or to the nitrogen atom of an (N-loweralkanoyl)amino group are not known.

DETAILED DESCRIPTION OF THE INVENTION

This invention relates to compounds of the formula ##STR1## wherein A isQR-- or BD--,

R is alkylene of one or three carbon atoms or oxyalkylene of two orthree carbon atoms,

Q is an unsubstituted amino group, a mono-substituted amino group, adi-substituted amino group, a cyclic amino groups or an (N-loweralkanoyl)amino group derived from a primary or secondary amine, Qcontaining not more than 12 carbon atoms and being bonded to R directlythrough a nitrogen atom therein,

B is an unsubstituted tetrazole ring,

D is a carbon-carbon bond or methylene (--CH₂ --),

m and n are zero or one, the sum of m and n is one and

X is hydrogen, methyl or ethyl, provided that the Q--R-- moiety isoptionally substituted by a single carboxylic acid group,

and pharmaceutically acceptable salts of such compounds. It is thecompounds in which Q is a basic nitrogen-containing group (an amine)which form the salts.

The term "lower" as used in connection with alkyl and alkylene groupsherein refers to such groups containing from one to four carbon atoms.Thus, lower alkanoyl herein refers to a group containing lower alkyl(containing up to four carbon atoms) bonded to carbonyl.

The hydrogen atom in B exists in tautomeric form on either the N¹ or N²atom, i.e. ##STR2## but is depicted herein, for convenience, asappearing on the N¹ atom.

When R is alkylene it is preferably methylene. The alkylene group mayfurthermore be bonded to a carboxyl group (in which case the group--R--Q is an amino acid group.

X in the compounds of the invention is preferably hydrogen or methyl.

Q preferably contains not more than 10 carbon atoms. When m is one, thegroup Q--R-- is preferably oriented in the 5, 6 or 7 position of thebenzo ring.

When n is one, the group Q--R-- is preferably oriented in the 3' or 4'position of the phenyl ring. It is also preferred that when n is one, Qis amino, N-lower alkylamino or N,N-dilower alkylamino (particularlysuch compounds in which the lower alkyl groups are methyl.

The preferred compounds of the invention include those in which Q isselected from amino, N-lower alkylamino, N,N-dilower alkylamino, N-loweralkylamino lower alkyleneamino, N-lower alkylamino loweralkylene-N-lower alkylamino, N,N-dilower alkylamino lower alkyleneamino,pyrrolidinyl, piperidinyl, N-methylpiperazinyl, N-phenylpiperazinyl,N-hydroxyethylpiperazinyl, nipecotamido, carboxyalkylamino, prolino,lower alkyl isonipecotato, lower alkyl isonicotinato,1-phenyl-8-N-1,3,8-triazaspiro[4,5]decan-4-onyl andpseudothiohydantoinyl.

The invention also includes the antimicrobial use of the compounds ofthe invention and certain compounds which are intermediates in thesynthesis of the final compounds of the invention (I).

The compounds of the invention are ordinarily white or yellowish tobrown or green crystalline or amorphous materials when purified. Theyare generally substantially insoluble in water or aliphatic hydrocarbonsand are more soluble in acetone, lower alcohols, halogenated solvents,benzene, N,N-dimethylformamide and the like. The hydrogen halide oralkyl halide tertiary ammonium salts of the compounds of the inventionhave appreciable solubility in water.

Among the microorganisms against which the compounds of the inventionare active are bacteria, fungi, helminths, coccidii, protozoans and thelike. They are particularly active, both in vitro and in vivo, againstbacteria. Thus, they can be used for disinfecting and sterilizing, forexample of medical and dental equipment, as components of disinfectingsolutions. The compounds are particularly useful as antibacterialagents. Some of the compounds are also active in vivo in animals. Forapplications in which water solubility is of importance, the salts areordinarily used.

The compounds of the invention (I) are prepared by several methods.Ordinarily the individual reactions are of types generically known tothe art, e.g. as methods for the preparation of amines. The reactioncondititons are chosen to a large extent for convenience and aregenerally within the skill of the art to determine, and suitablestarting materials are known or can be readily synthesized. Certain ofthe compounds (I) are prepared by further reaction of others of thecompounds (I) or from corresponding novel intermediates (II and IIIinfra), which themselves form aspects of the invention. The methods ofpreparation include the following:

A. The displacement of the halogen form an alkyl halide by ammonia or,preferably, a primary, secondary or tertiary amine. The startingmaterials are haloalkyl 3-phenylbenzofurans and haloalkyl2-nitro-3-phenylbenzofurans. The reactions are carried out at mild tomoderate temperatures of 0° to 125° C. in inert solvents such as loweralkyl ketones and aromatic hydrocarbons and monitored by chromatographyfor disappearance of starting material. When the starting material hasreacted, the reaction is quenched.

When the products of this and the other methods described hereinafterare unsubstituted in the 2-position, they are nitrated directly or,alternatively, first halogenated (e.g. brominated) in the 2-position,then nitrated. The direct nitration can be carried out with dinitrogentetroxide in a solvent such as acetonitrile at moderate temperature (0°to 30° C.). The 2-bromination can be carried out using bromine in asuitable solvent such as dichloromethane and the resulting intermediatecompound 2-nitrated using a combination of dinitrogen tetroxide in aninert solvent (such as acetic acid) in the presence of an alkene (e.g.cyclohexene).

The intermediate products of these reactions of the formula ##STR3##wherein A is QR-- or BD--, R is alkylene of one to three carbon atoms(preferably methylene) or oxyalkylene of two or three carbon atoms, Q isan (N-lower alkanoyl)amino group derived from a primary or secondaryamine, B is an unsubstituted tetrazole, D is a carbon-carbon bond ormethylene, m and n are zero or one, the sum of m and n is one, Z ishydrogen or bromine and X is hydrogen, methyl or ethyl are novel andconstitute a distinct aspect of the invention.

B. The reaction of a haloalkylbenzofuran with hexamethylenetetraminefollowed by decomposition of the resulting complex. The complex isdecomposed by reaction with a strong acid (such as a mineral acid, e.g.hydrochloric acid), as illustrated by Example 17.

C. Blocking and deblocking. When the substituent --R--Q in the finalcompound is to be amino acid, it is frequently desirable to block theacid until the amino group has been reacted. Deblocking is carried outlater if desired. Techniques for this type of conversion are well-knownto the amino acid and peptide synthesis art.

D. Preparation of an amine of formula I from the corresponding acidthrough the amide intermediate. More particularly this involves reactingan alkanoic acid-substituted or carboxylic acid-substituted benzofuranwith an acid chloride-producing reagent, e.g. thionyl chloride orphosphorus pentachloride, followed by reaction with ammonia or an amineto provide an amide and finally reduction, e.g. with diborone to providean amine of formula I.

E. Acylation-reduction of the invention in which --Q is --NH₂ or --NHR'can be acylated by reaction with the anhydride of a lower alkanoic acid,##STR4## to form respectively the compounds in which --Q is ##STR5## andthen reducing (e.g. with diborane) to form the compounds in which --Q is##STR6## R' and R" are lower alkyl groups herein.

F. Preparation of an amino acid of the invention from analdehyde-substituted 2-nitro-3-phenylbenzofuran. The aldehyde group isconverted to a cyanohydrin, the hydroxy displaced by an amine group andthe cyano group hydrolyzed to provide the acid function.

G. Preparation of a tetrazole-substituted-3-phenylbenzofuran of theinvention from a cyano-substituted-3-phenylbenzofuran. Thecyano-substituted compound is reacted with sodium azide inN,N-dimethylformamide in the presence of ammonium chloride to providethe corresponding tetrazole-substituted-3-phenylbenzofuran. Thisintermediate (which is unsubstituted in the 2-position of the benzofuranmoiety) is converted to the 2-nitro compound of formula I through the2-bromo intermediate or directly by reaction with dinitrogen tetraoxide(as described previously).

The intermediate compounds ##STR7## of this route (wherein Z is hydrogenor bromine and D is a carbon-carbon bond or methylene) are novel andconstitute an additional aspect of the invention.

H. Preparation of the compounds of the invention wherein --R-- isoxyalkylene. It is preferred to start withhydroxy-substituted-3-phenylbenzofurans, particularlyhydroxy-substituted-2-nitro-3-phenylbenzofurans and react them in thepresence of a strong base such as sodium hydride with a haloalkylamine.These reactions are generally carried out in an inert solvent such asglyme at the reflux temperature of the reaction mixture.

I. The compounds of the invention are frequently isolated as salts,including hydrated salts. These are readily converted to the free baseby neutralizing with a dilute base, such as dilute aqueous sodiumhydroxide solution.

J. Preparation of the pharmaceutically acceptable salts of theinvention. The salts are readily prepared byh reaction of thecorresponding free base (i.e. amine) compound of formula I with theappropriate hydrogen halide or alkyl halide (the latter ordinarilycontaining not more than about 20 carbon atoms and preferably not morethan 12 carbon atoms), optionally in a suitable solvent and evaporatingto dryness. Other salts which are not pharmaceutically acceptable may beuseful for the synthesis of the basic compounds of the invention orother, acceptable salts or other useful intermediates.

The antimicrobial activity of the compounds is evaluated using avariation of the original agar-plate diffusion method of Vincent andVincent (e.g. see Vincent, J. G., and Vincent, Helen W., Proc. Soc.Exptl. Biol. Med. 55:162-164, 1944, and Davis, B. D., and Mingioli, E.S., J. Bac. 66:129-136, 1953). Using this test, the compounds of theinvention have been found to have a broad spectrum of activity againstboth gram-positive and gram-negative microorganisms. The procedureprovides information on the amount of a compound required to givecomplete inhibition, partial inhibition or no inhibition of microbialgrowth on agar plates. The microbial growth on each plate is readvisually, and minimal inhibitory concentrations are recorded.

The microorganisms used are: Staphylococcus aureus, Bacillus subtilus,Pseudomonas aeruginosa, Escherichia coli, Streptococcus sp. (strainsisolated from dental caries in rats or hamsters at the NationalInstitute of Dental Health and grown in PFY or APT agar) Asperigillusniger, Candida albicans, Mima polymorpha, Herellea vaginicola,Klebsiella pneumoniae and Streptococcus fecaelis.

These are selected representatives of various bacterial and fungalclasses and broad spectrum activity can be predicted as a result ofactivity against them. All of the compounds of the invention possessantimicrobial activity towards one or more of them. The compoundsmaintain high activity against the microorganisms either in the absenceor presence of ten percent horse serum.

The in vivo antimicrobial activity is determined against infectionsproduced by Streptococcus pyogenes C-203 and Staphylococcus aureus(Smith) or other bacterial species. The species used is determined bythe in vitro antimicrobial spectrum of the compound. Groups of 5 or 10mice, 18-22 g., are infected intraperitoneally with the test culture.Treatment consists of three oral injections 1, 6 and 24 hours afterinfection. All mice are observed for extended periods, e.g. for twoweeks, and deaths recorded at daily intervals. Control groups consist ofone infected, non-treated group and other infected groups receivingvarying dosages of the reference standard.

The acute oral toxicity of the compounds of the invention generally ismoderate to low compared with the effective oral dose, and they have agood to excellent therapeutic ratio.

The compounds of the invention may be formulated by incorporating theminto a conventional pharmaceutical carrier material, either organic orinorganic, which is suitable for oral or parenteral application. For invitro or topical use, simple aqueous solutions or suspensions are mostconveniently employed. For this purpose, concentrations of the order of100 parts per million up to about 5 parts per thousand are suitable, andthe formulation is used by immersing the object to be treated therein,or by local application to an infected area. The amount of compound tobe used for, e.g. oral treatment of a microbal infection will be aneffective amount less than a toxic amount. The amount to be administeredto a subject and route of administration to control an infection willdepend on the species of organism, the sex, weight, physical conditionof the subject, the locus of the infection, and many other factors, butthis judgement is well within the skill of the art. Usually the amountwill be less than 100 mg/kg per dose. Conveniently the oral treatment isadministered in the form of the usual pharmaceutical preparation such ascapsules, tablets, emulsions, solutions, suppositories and the like.Excipients, fillers, coatings, etc., are employed with tablets orcapsules, as is well known in the art.

It is often advantageous to combine the compounds of this invention withother antimicrobial compounds such as coccidiostats, anthelmintics,antifungals, antibiotics, steroids or antibacterial agents, or tocombine more than one compound described herein in a single formulation.

Certain of the compounds are also active antiparasitics as shown byactivity in laboratory tests versus the protozoan Trichomonas sp. Inview of the outstanding antimicrobial activity of the compounds, theywould also be expected to be effective growth promoters in variousanimal and bird species.

The following examples are given for the purpose of illustrating theinvention, but are in no way limiting thereof. The melting points areuncorrected and are in degrees Centigrade.

EXAMPLE 1

A stirred mixture of 5 g. (0.015 mole) of5-bromomethyl-2-nitro-3-phenylbenzofuran and 7.5 g. (0.075 mole) ofN-methylpiperazine in 15 ml. of ethanol is heated at 45° C. for 1 hour.The reaction mixture is evaporated to provide a residue which isextracted with diethyl ether. The ether extracts are washed with waterand with a saturated sodium chloride solution and dried. Evaporation ofthe ether solution provides a yellow oil which is dissolved in diethylether and treated while stirring with a solution of 4N hydrochloric acidin isopropanol until the reaction is complete. The solid is stirred inhot ethanol while adding water until it is all in solution. Coolingprovides a fluffy yellow product,1-methyl-4-(2-nitro-3-phenyl-5-benzofuranylmethyl)piperazinedihydrochloride dihydrate, m.p. 269°-276° C. (dec.), having thestructure ##STR8##

    ______________________________________    Analysis:          % C      % H    % N    ______________________________________    Calculated for C.sub.20 H.sub.27 O.sub.5 N.sub.3 Cl.sub.2 :                       52.2;    5.9;   9.1    Found:             52.0;    5.8;   9.1.    ______________________________________

EXAMPLE 2

Using the method of Example 1, 5-bromomethyl-2-nitro-3-phenylbenzofuranis reacted with pyrrolidine in ethanol to provide yellow crystals of2-nitro-3-phenyl-5-(1-pyrrolidylmethyl)benzofuran, m.p. 111°-112.5° C.,having the structure ##STR9##

    ______________________________________    Analysis:         % C       % H    % N    ______________________________________    Calculated for C.sub.19 H.sub.18 O.sub.3 N.sub.2 :                      70.8;     5.6;   8.7    Found:            70.8;     5.7;   8.6.    ______________________________________

EXAMPLE 3

Using the method of Example 1, 5-bromomethyl-2-nitro-3-phenylbenzofuranis reacted with 3-(N,N-diethylamino)propylamine in ethanol to providelight tan crystals of5-[3-(N,N-diethylamino)propylaminomethyl]-2-nitro-3-phenylbenzofurandihydrochloridemonohydrate, m.p. 143°-150° C., having the structure##STR10##

    ______________________________________    Analysis:          % C      % H    % N    ______________________________________    Calculated for C.sub.22 H.sub.31 O.sub.4 N.sub.3 Cl.sub.2 :                       55.9;    6.6;   9.0    Found:             55.5;    7.0;   9.0.    ______________________________________

EXAMPLE 4

Using the method of Example 1, 5-bromomethyl-2-nitro-3-phenylbenzofuranis reacted with N-hydroxyethylpiperazine in ethanol to provide4-(2-nitro-3-phenyl-5-benzofuranylmethyl)-1-piperazineethanoldihydrochloride monohydrate, m.p. 248°-266° C. (dec.), having thestructure ##STR11##

    ______________________________________    Analysis:          % C      % H    % N    ______________________________________    Calculated for C.sub.21 H.sub.27 O.sub.5 N.sub.3 Cl.sub.2 :                       53.4;    5.8;   8.9    Found:             53.9;    5.7;   9.0.    ______________________________________

EXAMPLE 5

Using the method of Example 1, 5-bromomethyl-2-nitro-3-phenylbenzofuranis reacted with N-phenylpiperazine in ethanol to provide yellow needlesof 4-(2-nitro-3-phenyl-5-benzofuranylmethyl)-1-phenylpiperazine, m.p.155°-157° C., having the structure ##STR12##

    ______________________________________    Analysis:         % C       % H    % N    ______________________________________    Calculated for C.sub.25 H.sub.23 O.sub.3 N.sub.3 :                      72.6;     5.6;   10.2    Found:            72.5;     5.6;   10.2.    ______________________________________

EXAMPLE 6

Using the method of Example 1, 5-bromomethyl-2-nitro-3-phenylbenzofuranis reacted with morpholine in ethanol to provide yellow crystals ofN-(2-nitro-3-phenyl-5-benzofuranylmethyl)-morpholine, m.p. 151°-154° C.,having the structure ##STR13##

    ______________________________________    Analysis:         % C       % H    % N    ______________________________________    Calculated for C.sub.19 H.sub.18 O.sub.4 N.sub.2 :                      67.4;     5.4;   8.3    Found:            67.3;     5.3;   8.3.    ______________________________________

EXAMPLE 7

Using the method of Example 1, 5-bromomethyl-2-nitro-3-phenylbenzofuranis reacted with N,N'-dimethylaminoethylamine in ethanol to provideyellow solid5-(N,N'-dimethylaminoethylaminomethyl)-2-nitro-3-phenylbenzofurandihydrochloride hemihydrate, m.p. 224°-227° C. (dec.), having thestructure ##STR14##

    ______________________________________    Analysis:           % C      % H    % N    ______________________________________    Calculated for C.sub.19 H.sub.23 O.sub.3 N.sub.3 Cl.sub.2.1/2H.sub.2                        54.2;    5.7;   10.0    Found:              54.0;    5.3;    10.2.    ______________________________________

EXAMPLE 8

To a 1.9 g. (0.0056 mole) sample ofN-(2-nitro-3-phenyl-5-benzofuranylmethyl)morpholine (the product ofExample 6) in 100 ml. of acetone is added 1.0 g. of methyliodide. Aftersetting for one week, an additional 1.0 g. of methyliodide is added.After 1 day of stirring, the precipitated solid is separated byfiltration and extracted with 300 ml. of refluxing ethanol to provideyellow crystals ofN-methyl-N-(2-nitro-3-phenyl-5-benzofuranylmethyl)morpholinium iodide,m.p. 226°-230° C., having the structure ##STR15##

    ______________________________________    Analysis:         % C       % H    % N    ______________________________________    Calculated for C.sub.20 H.sub.21 IN.sub.2 O.sub.4 :                      50.0;     4.4;   5.8    Found:            50.2;     4.5;    6.0.    ______________________________________

EXAMPLE 9

Using the method of Example 8,4-(2-nitro-3-phenyl-5-benzofuranylmethyl)-1-phenylpiperazine (theproduct of Example 5) is reacted with methyliodide in acetone to provide4-methyl-4-(2-nitro-3-phenyl-5-benzofuranylmethyl)-1-phenylpiperaziniumiodide, m.p. 120°-125° C., having the structure ##STR16##

    ______________________________________    Analysis:         % C       % H    % N    ______________________________________    Calculated for C.sub.26 H.sub.26 IN.sub.3 O.sub.3 :                      56.2;     4.7;   7.6    Found:            56.0;     4.9;    7.2.    ______________________________________

EXAMPLE 10

Using the method of Example 8,2-nitro-3-phenyl-5-(1-pyrrolidylmethyl)benzofuran (the product ofExample 2) is reacted with methyliodide in acetone to provide tan solidN-methyl-N-(2-nitro-3-phenyl-5-benzofuranylmethyl)pyrrolidinium iodide,m.p. 235°-237° C., having the structure ##STR17##

    ______________________________________    Analysis:         % C       % H    % N    ______________________________________    Calculated for C.sub.20 H.sub.21 IN.sub.2 O.sub.3 :                      51.7;     4.6;   6.0    Found:            51.8;     4.6;    6.1.    ______________________________________

EXAMPLE 11

A mixture of 1.7 g. (0.0066 mole) of1-phenyl-1,3,8-triazaspiro[4.5]decan-4-one (available from the AldrichChemical Company) and 2 g. (0.006 mole) of5-bromomethyl-2-nitro-3-phenylbenzofuran in 50 ml. of acetone is heatedat its reflux temperature for about 75 hours. The mixture is cooled to20° C. and filtered. The precipitate is washed with acetone to provideyellow1-phenyl-8-N-[(2-nitro-3-phenylbenzofuran-5-yl)methyl]-1,3,8-triazaspiro[4.5]decan-4-onehydrobromide salt, m.p. 243°-244° C., having the structure ##STR18##after recrystallization from ethanol.

    ______________________________________    Analysis:              % C    % H     % N    ______________________________________    Calculated for C.sub.28 H.sub.26 N.sub.4 O.sub.4.HBr.C.sub.2 H.sub.6                           59.1;  5.4;    9.2    Found:                 58.7;  5.3;     9.3.    ______________________________________

EXAMPLE 12

A mixture of 1.04 g. (0.0066 mole) of ethyl isonipecotate and 2 g.(0.006 mole) of 5-bromomethyl-2-nitro-3-phenylbenzofuran in 100 ml. ofacetone is heated at reflux for 40 hours. The mixture is cooled and thenevaporated to provide a residue which is diluted with diethyl ether. Ayellow precipitate is separated by filtration to provide ethylN-(2-nitro-3-phenylbenzofuran-5-yl)isonipecotate hydrobromide, m.p.220°-221° C., having the structure ##STR19##

    ______________________________________    Analysis:           % C      % H    % N    ______________________________________    Calculated for C.sub.23 H.sub.24 N.sub.2 O.sub.5.HBr:                        56.4;    5.1;   5.7    Found:              56.3;    5.4;    5.6.    ______________________________________

EXAMPLE 13

A mixture of 1.53 g. (0.0099 mole) of ethylisonicotinate (available fromthe Aldrich Chemical Company) and 3 g. (0.009 mole) of5-bromomethyl-2-nitro-3-phenylbenzofuran in 100 ml. of acetone is heatedat its reflux temperature for about 50 hours. The mixture is cooled andfiltered to separate the yellow solid. The solid is washed several timeswith acetone. The yellow solid is ethylN-[(2-nitro-3-phenylbenzofuran-5-yl)methyl]isonicotinium bromide, m.p.238°-239° C., having the structure ##STR20##

    ______________________________________    Analysis:          % C      % H    % N    ______________________________________    Calculated for C.sub.23 H.sub.19 BrN.sub.2 O.sub.5 :                       57.1;    3.9;   5.8    Found:             56.9;    3.8;    5.7.    ______________________________________

EXAMPLE 14

A mixture of 0.8 g. of nipecotamide (available from the Aldrich ChemicalCompany) and 2 g. of 5-bromomethyl-2-nitro-3-phenylbenzofuran in 100 ml.of acetone is heated at its reflux temperature for about 48 hours. Themixture is cooled, and the yellow precipitate is separated byfiltration. The filtrate is evaporated to provide a residue. The residueis separated by chromatography in silica gel eluting withdichloromethane. The product is readily separated from startingmaterials and shown to beN-[(2-nitro-3-phenylbenzofuran-5-yl)methyl]nipecotamide hemihydrate,m.p. 76°-77° C., having the structure ##STR21## by infrared and nuclearmagnetic resonance spectral analysis.

    ______________________________________    Analysis:             % C    % H      % N    ______________________________________    Calculated for C.sub.21 H.sub.21 N.sub.3 O.sub.4.1/2H.sub.2 O:                          64.9;  5.7;     10.8    Found:                64.3;  5.7;      10.4.    ______________________________________

EXAMPLE 15

A mixture of 2 g. (0.006 mole) of5-bromomethyl-2-nitro-3-phenylbenzofuran, 0.9 g. (0.006 mole) ofL-proline methylesterhydrochloride (available from the Aldrich ChemicalCompany) and 1.2 g. (0.012 mole) of triethylamine in 100 ml. of tolueneis heated at reflux for about 100 hours. The mixture is extracted threetimes with 50 ml. portions of water. The organic layer is then extractedrepeatedly with 50 ml. portions of 3N hydrochloric acid to remove all ofthe yellow product from the toluene layer. The aqueous layer isneutralized with 10 percent sodium carbonate solution. The aqueous layeris then extracted with dichloromethane until the water is colorless. Thedichloromethane layer is dried, then evaporated to provide a residuewhich is diluted with diethyl ether to provide a brownish precipitate.The solid is removed by filtration, and the filtrate is concentrated toprovide a residue. The residue is suspended in 50 ml. of concentratedhydrochloric acid diluted 1:1 with water. The mixture is heated at 90°C. for three hours. The mixture is cooled and filtered to provide ayellow precipitate. The precipitate is washed with water to provideN-[(2-nitro-3-phenylbenzofuran-5-yl)methyl]-L-proline hydrochloridehydrate, m.p. 109°-110° C., having the structure ##STR22##

    ______________________________________    Analysis:          % C       % H    % N    ______________________________________    Calculated for C.sub.20 H.sub.20 ClN.sub.2 O.sub.6 :                       57.2;     4.8;   6.6    Found:             57.2;     5.5;    6.6.    ______________________________________

EXAMPLE 16

A mixture of 0.7 g. (0.006 mole) of pseudothiohydantoin (available fromthe Aldrich Chemical Company) and 2 g. (0.006 mole) of5-bromomethyl-2-nitro-3-phenylbenzofuran in 50 ml. of toluene is heatedat reflux for about 16 hours. The mixture is cooled, and the light brownsolid is removed by filtration. The filtrate is evaporated to provide aresidue which is separated into starting material and product bychromatography on silica gel, eluting with benzene. The yellow solidobtained is recrystallized from ethanol to provide yellow solidN-[(2-nitro-3-phenylbenzofuran-5-yl)methyl]pseudothiohydantoin, m.p.204°-205° C., having the structure ##STR23##

    ______________________________________    Analysis:         % C       % H    % N    ______________________________________    Calculated for C.sub.18 H.sub.13 N.sub.3 O.sub.4 S:                      59.1;     3.5;   11.4    Found:            58.5;     3.8;    11.2.    ______________________________________

EXAMPLE 17

To a solution of 3.3 g. (0.010 mole) of5-bromomethyl-2-nitro-3-phenylbenzofuran in 50 ml. of chloroform isadded 1.4 g. (0.010 mole) of hexamethylenetetramine in 25 ml. ofchloroform. After stirring for 16 hours a solid precipitate is separatedby filtration and rinsed with chloroform. The solid is suspended in amixture of 100 ml. of 95 percent ethanol and 10 ml. of concentratedhydrochloric acid and stirred. The solution is evaporated to dryness toprovide a residue which is recrystallized twice from 3N hydrochloricacid. The product is yellow crystals of5-aminomethyl-2-nitro-3-phenylbenzofuran hydrochloride hydrate, m.p.246°-254° C. (dec.), having the structure ##STR24##

    ______________________________________    Analysis:             % C    % H      % N    ______________________________________    Calculated for C.sub.15 H.sub.12 N.sub.2 O.sub.3.HCl.11/2H.sub.2 O:                          54.3;  4.9;     8.4    Found:                54.6;  4.9;      8.6.    ______________________________________

EXAMPLE 18

A mixture of 1.04 g. (0.006 mole) of L-valine t-butyl ester and 2 g.(0.006 mole) of 5-bromomethyl-2-nitro-3-phenylbenzofuran in 100 ml. ofacetone is heated at reflux for about 50 hours. The mixture is cooled,and the solvent is evaporated to provide a residue. The product isseparated from the residue by chromatography on silica gel, eluting withbenzene. The product is identified by infrared spectral analysis as thetertiary-butyl ester ofN-[(2-nitro-3-phenylbenzofuran-5-yl)methyl]valine. This residue isdissolved in 75 ml. of 6N hydrochloric acid and 25 ml. of ethanol byheating at 75° C. for 4 hours. The reaction mixture is evaporated toprovide a residue which is recrystallized from ethanol. The product islight yellow solid N-[(2-nitro-3-phenylbenzofuran-5-yl)methyl]valinehydrochloride, m.p. 183°-184° C., having the structure ##STR25##

    ______________________________________    Analysis:            % C      % H    % N    ______________________________________    Calculated for C.sub.20 H.sub.20 N.sub.2 O.sub.5.HCl.1/2 H.sub.2 O:                         58.0;    5.3;   6.8    Found:               58.0;    5.4;    6.8.    ______________________________________

EXAMPLE 19

A mixture of 5 ml. of acetic anhydride and 0.3 g. of5-aminomethyl-2-nitro-3-phenylbenzofuran hydrochloride (from Example 17)is heated on a steam bath for about 30 minutes. The mixture is thenpartially evaporated to provide a residue which is treated with aqueousisopropanol to form yellow crystals of5-acetamidomethyl-2-nitro-3-phenylbenzofuran, m.p. 201°-203° C., havingthe structure ##STR26##

    ______________________________________    Analysis:         % C       % H    % N    ______________________________________    Calculated for C.sub.17 H.sub.14 N.sub.2 O.sub.4 :                      65.8;     4.5;   9.0    Found:            65.6;     4.5;    9.0.    ______________________________________

EXAMPLE 20 Step A

A stirred mixture of 2.7 g. (0.010 mole) of2-nitro-3-phenylbenzofuran-7-aldehyde (described in Belgian Pat. No.846,502, Example 13) and 20 ml. of diethyl ether is treated with 1.6 g.(0.015 mole) of sodium bisulfite in 10 ml. of water. After 30 minutes,30 ml. of chloroform is added, followed by 1.5 g. (0.030 mole) of sodiumcyanide in 5 ml. of water after an additional 30 minutes. About 0.7 g.of sodium bisulfite is added 1.5 hours later, and the mixture is cooledto 0° C. 30 minutes after the bisulfite addition and maintained forabout 16 hours. The organic layer is separated, washed with aqueoussodium bisulfite solution, then with water, and dried over magnesiumsulfate. Evaporation of the solution provides a solid which isrecrystallized from a chloroform-heptane mixture to provide yellowcrystals of α-hydroxy-2-nitro-3-phenylbenzofuran-7-acetonitrile, m.p.137°-139° C.

    ______________________________________    Analysis:         % C       % H    % N    ______________________________________    Calculated for C.sub.16 H.sub.10 N.sub.2 O.sub.4 :                      65.3;     3.4;   9.5    Found:            64.9;     3.3;    9.5.    ______________________________________

Step B

A mixture of 5 g. (0.02 mole) ofα-hydroxy-3-phenylbenzofuran-7-acetonitrile and 2 g. of methylamine in100 ml. of dichloromethane is heated to its reflux temperature, thenstirred at 20° C. for 16 hours. The mixture is evaporated to provide aresidue which is dissolved in benzene which has been previouslysaturated with hydrogen chloride. The mixture is heated for 15 minuteson a steam bath, then saturated with petroleum ether, whereupon a whiteprecipitate of α-methylamino-3-phenylbenzofuran-7-acetonitrilehydrochloride forms. A 5 gram sample of this intermediate is suspendedin 50 ml. of glacial acetic acid, 5 g. of dinitrogen tetraoxide isadded, and the mixture is stirred for 24 hours at 20° C. The volatilesare removed by evaporation to provide a residue which is dissolved in 10ml. of acetic acid, and the mixture is heated at its reflux temperaturewhile adding 30 ml. of 12N hydrochloric acid. Refluxing is continued for1 hour, then the mixture is cooled. A green solid is obtained which isrecrystallized from glacial acetic acid to provide light green crystalsof α-methylamino-2-nitro-3-phenylbenzofuran-7-acetic acid, m.p. 237° C.(dec.), having the structure ##STR27##

    ______________________________________    Analysis:           % C      % H    % N    ______________________________________    Calculated for C.sub.17 H.sub.14 N.sub.2 O.sub.5.H.sub.2 O:                        59.3;    4.6;   8.1    Found:              58.7;    4.3;    7.9.    ______________________________________

EXAMPLE 21 Step A

A mixture of 61.4 g. (0.28 mole) of 5-cyano-3-phenylbenzofuran(described in U.S. Pat. No. 4,067,993, Example 1), 16.5 g. (0.31 mole)of ammonium chloride and 20.2 g. (0.31 mole) of sodium azide in 250 ml.of N,N-dimethylformamide is stirred at 110°14 120° C. for 16 hours. Themixture is cooled to about 20° C. and poured into about 1 liter ofwater. A light brown solid forms which is collected by filtration,washed with water, and then recrystallized from ethanol to provide browncrystals of 3-phenyl-5-(1H-tetrazol-5-yl)benzofuran.

Step B

To a solution of 10 g. (0.045 mole) of3-phenyl-5-(1H-tetrazol-5-yl)benzofuran in 250 ml. of hot dioxane isadded 400 ml. of hot dichloromethane. To this solution is added asolution of 7.3 g. (0.045 mole) of bromine in 20 ml. of dichloromethanedropwise over a period of 30 minutes. The resulting solution is stirredfor 20 hours. The solid product(2-bromo-3-phenyl-5-(1H-tetrazol-5-yl)benzofuran) is collected byfiltration and dried.

Step C

To a solution of 3 g. of the product of Step B in 600 ml. of hot aceticacid is added 1 g. of cyclohexene and 1 g. of dinitrogen tetraoxide. Themixture is heated at its reflux temperature for 16 hours. An additional1 g. of cyclohexene and 1 g. of dinitrogen tetraoxide is added to themixture, and heating is continued for 5 hours. The solution is pouredinto 2 liters of water and stirred. The resulting yellow precipitate isisolated by filtration, washed with water and dried, then recrystallizedfrom aqueous isopropanol to provide yellow crystals of2-nitro-3-phenyl-5-(1H-tetrazol-5-yl)benzofuran, m.p. 215°-217° C.,having the structure ##STR28##

    ______________________________________    Analysis:        % C        % H    % N    ______________________________________    Calculated for C.sub.15 H.sub.9 N.sub.5 O.sub.3 :                     58.6;      2.9;   22.8    Found:           57.9;      3.2;    21.8.    ______________________________________     The structure of the product is confirmed by infrared and mass spectral     analysis. The presence of some isopropanol and some water is determined.

EXAMPLE 22

To a solution of 2 g. (0.008 mole) of6-hydroxy-2-nitro-3-phenylbenzofuran (described in U.S. Pat. No.3,927,037, Example 2) in 25 ml. of glyme is added a solution of 0.016mole of sodium hydride in 20 ml. of glyme. To this solution is added 1.2g. (0.008 mole) of N,N-dimethyl-N-(2-chloroethyl)amine hydrochloride.The mixture is heated to its reflux temperature and maintained at refluxfor 6 hours. The reaction mixture is extracted thrice with diethylether, the ether is washed with water and saturated sodium chloridesolution and then dried. The ether extracts are treated while stirringwith hydrogen chloride gas. A yellow residue is separated and washedwith diethyl ether, then recrystallized from isopropanol to provideN,N-dimethyl-2-(2-nitro-3-phenyl-6-benzofuranyloxy)ethylaminehydrochloride, m.p. 231°-235° C. (dec.), having the structure ##STR29##

    ______________________________________    Analysis:             % C     % H    % N    ______________________________________    Calculated for C.sub.18 H.sub.19 ClN.sub.2 O.sub.4.1/4H.sub.2 O:                          58.9;   5.4;   7.6    Found:                58.7;   5.4;    7.6.    ______________________________________

EXAMPLE 23

To a suspension of 1.2 g. of sodium hydride in 25 ml. of glyme is addeda solution of 2 g. (0.008 mole) of 6-hydroxy-2-nitro-3-phenylbenzofuranin 25 ml. of glyme, 1.9 g. (0.012 mole) of3-(N,N-dimethylamino)propylchloride hydrochloride is added and themixture is heated to its reflux temperature and maintained at reflux for2 hours. The mixture is then evaporated, and the residue is diluted withwater. The aqueous residue is extracted 4 times with diethyl ether. Theether extracts are washed with water and saturated sodium chloridesolution and dried. The ether solution is treated with hydrogen chloridegas, and a solid precipitate which forms is separated by decantation andrecrystallized from water. The yellow product solid isN,N-dimethyl-3-(2-nitro-3-phenyl-6-benzofuranyloxy)propylaminehydrochloride hydrate, m.p. 221°-224° C., having the structure ##STR30##

    ______________________________________    Analysis:            % C     % H     % N    ______________________________________    Calculated for C.sub.19 H.sub.21 ClN.sub.2 O.sub.4.11/4 H.sub.2 O:                         57.1;   5.9;    7.0    Found:               56.9;   5.9;    6.9.    ______________________________________

EXAMPLE 24 Step A

A mixture of 40 g. of 4-methylphenol, 100 g. of4-bromo-α-bromoacetophenone (both available from the Aldrich ChemicalCompany), 80 g. of potassium carbonate and 1 liter of acetone is heatedto its reflux temperature and maintained at reflux with stirring for 64hours. To this mixture is added 10 g. more of potassium carbonate, andrefluxing is continued for an additional 5 hours. The mixture is cooled,filtered and evaporated to provide a residue ofα-(4-methylphenoxy)-4-bromoacetophenone as light brown crystals afterrecrystallization from aqueous isopropanol.

Step B

The product of Step A is mixed with 500 g. of polyphosphoric acid andheated at 100° C. for 2 hours with stirring, then decanted into 1 literof ice water. The aqueous mixture is extracted with diethyl ether, andthe ether extracts are washed with saturated sodium chloride solutionand dried. The solution is evaporated to provide a brown oil which isdistilled at 160°-170° C. at 0.25 mm. of Hg to provide3-(4-bromophenyl)-5-methylbenzofuran.

Step C

The product of Step B is reacted in a Grignard reaction with 5 g. ofmagnesium turnings in 25 ml. of tetrahydrofuran (by adding the productof Step B in 150 ml. of tetrahydrofuran at a rate sufficient to sustainrefluxing). Refluxing is continued for an additional 3 hours, afterwhich the mixture is stirred overnight at about 20° C. To this reactionmixture is added gaseous carbon dioxide over a period of 1 hour, themixture being maintained at reflux during the second half of the hour.The reaction mixture is cooled and cautiously added to 50 ml. of 6Nhydrochloric acid, then evaporated to provide a residue which isrecrystallized from acetic acid to provide tan crystals of4-(5-methyl-3-benzofuranyl)benzoic acid.

Step D

A mixture of 22.5 g. of the product of Step C, 2 g. of cupric nitrateand 100 ml. of acetonitrile is cooled with an ice bath, and 10 g. ofdinitrogen tetraoxide in 20 ml. of acetonitrile is added over a periodof 10 minutes. The ice bath is removed and the mixture is stirred at 20°C. for 4 hours, evaporated, partially cooled and filtered. The residueis recrystallized from aqueous N,N-dimethylformamide. The product isyellow crystals of 4-(5-methyl-2-nitro-3-benzofuranyl)benzoic acid, m.p.258° C. (dec.).

    ______________________________________    Analysis:        % C        % H    % N    ______________________________________    Calculated for C.sub.16 H.sub.11 NO.sub.5 :                     64.6;      3.7;   4.7    Found:           64.2;      3.7;    4.8.    ______________________________________

Step E

To a solution of the product of Step D in 200 ml. of tetrahydrofuran isadded 150 ml. of 1N diborane. The mixture is heated and maintained atreflux for 2 hours, 100 ml. of 3N sulfuric acid is added and refluxingis continued for an additional hour. The mixture is then evaporated toprovide a residue which is recrystallized from aqueous isopropanol toform yellow crystals of3-(4-hydroxymethyl)phenyl-5-methyl-2-nitrobenzofuran, m.p. 145°-147° C.

    ______________________________________    Analysis:        % C        % H    % N    ______________________________________    Calculated for C.sub.16 H.sub.13 NO.sub.4 :                     67.8;      4.6;   4.6    Found:           67.4;      4.6;    4.7.    ______________________________________

Step F

To a 6 g. sample of the product of Step E is added slowly 20 ml. ofthionyl chloride. The mixture is then heated on a steam bath for 15minutes and evaporated to provide a residue which is treated withbenzene and re-evaporated twice. The resulting residue crystallizes whensuspended in ethanol. The product is3-(4-chloromethyl)phenyl-5-methyl-2-nitrobenzofuran, m.p. 116°-120° C.

    ______________________________________    Analysis:          % C       % H    % N    ______________________________________    Calculated for C.sub.16 H.sub.12 ClNO.sub.3 :                       63.7;     4.0;   4.6    Found:             63.8;     4.0;    4.6.    ______________________________________

Step G

A suspension of 1 g. of the product of Step F in 15 ml. of ethanol and 5g. of diethylamine is heated on a steam bath for 2 hours. The mixture isevaporated to provide a residue which is recrystallized from aqueousisopropanol to form yellow crystals of3-(4-diethylaminomethyl)phenyl-5-methyl-2-nitrobenzofuran, m.p.117°-119° C., having the structure ##STR31##

    ______________________________________    Analysis:         % C       % H    % N    ______________________________________    Calculated for C.sub.20 H.sub.22 N.sub.2 O.sub.3 :                      71.0;     6.6;   8.3    Found:            70.9;     6.5;   8.0.    ______________________________________

EXAMPLE 25

To a solution of 1 g. of3-(4-chloromethyl)phenyl-5-methyl-2-nitrobenzofuran (described in Step Fof the previous example) in 25 ml. of ethanol is added 25 ml. of ethanolwhich is saturated with methylamine gas. Methylamine is bubbled into thereaction mixture over 20 minutes while heating on a steam bath, andheating is continued for 2 hours. The reaction mixture is evaporated,the residue is dissolved in chloroform and the solution is washed withdilute sodium hydroxide solution and dried. The dried solution isevaporated to provide a residue which is dissolved in isopropanol andtreated with hydrogen chloride gas until the solution is acidic. Yellowcrystals of 5-methyl-3-(4-methylaminomethyl)phenyl-2-nitrobenzofuranhydrochloride, m.p. 250° C. (dec.), are formed. The structure of thisproduct is as follows ##STR32##

    ______________________________________    Analysis:           % C      % H    % N    ______________________________________    Calculated for C.sub.17 H.sub.16 N.sub.2 O.sub.3.HCl:                        61.4;    5.1;   8.4    Found:              61.9;    5.3;   8.2.    ______________________________________

EXAMPLE 26 Step A

To a 2.4 g. sample of 4-(5-methyl-2-nitro-3-benzofuranyl)benzoic acid(described in Step D of Example 24) is added 15 ml. of thionyl chlorideand 3 drops of N,N-dimethylformamide. The mixture is heated on a steambath for 30 minutes, then evaporated to provide a residue. The residueis dissolved in 50 ml. of chloroform, ammonia gas is bubbled into thesolution for 15 minutes, an additional 200 ml. of chloroform is added,and the solution is washed twice with water and dried. The solution isthen evaporated to provide a yellow residue which is recrystallized fromaqueous N,N-dimethylformamide. The product is yellow crystals of4-(5-methyl-2-nitro-3-benzofuranyl)benzamide, m.p. 227°-229° C.

    ______________________________________    Analysis:         % C       % H    % N    ______________________________________    Calculated for C.sub.16 H.sub.12 N.sub.2 O.sub.4 :                      64.9;     4.1;   9.4    Found:            64.6;     4.0;   9.6.    ______________________________________

Step B

To a suspension of 1.3 g. of the product of Step A in 30 ml. oftetrahydrofuran is added 20 ml. of 1N diborane in tetrahydrofuran. Thesolution is stirred at 20° C. for 20 hours, then 20 ml. of 6Nhydrochloric acid is added. The mixture is heated at reflux for 1/2hour, then evaporated to provide a residue which is treated with 10percent sodium hydroxide solution until basic. The resulting aqueoussolution is extracted with chloroform, and the extracts are dried, thenevaporated to provide a residue which is recrystallized from achloroform-heptane mixture to provide a first crop of 0.2 g. of yellowsolid which is found to be starting material. A second crop of 0.7 g. ofyellow crystal is obtained which is dissolved in isopropanol and treatedwith gaseous hydrogen chloride to provide yellow crystals of3-(4-aminomethyl)phenyl-5-methyl-2-nitrobenzofuran hydrochloride, m.p.271° C. (dec.), having the formula ##STR33##

    ______________________________________    Analysis:           % C      % H    % N    ______________________________________    Calculated for C.sub.16 H.sub.14 N.sub.2 O.sub.3.HCl:                        60.3;    4.7;   8.8    Found:              60.1;    4.8;   8.8.    ______________________________________

EXAMPLE 27

Using the method of Example 1, and starting with7-bromomethyl-2-nitro-3-phenylbenzofuran and N-methylaminoethylamine theproduct obtained is7-(N-methylaminoethylaminomethyl)-2-nitro-3-phenylbenzofurandihydrochloride having the structure ##STR34##

EXAMPLE 28

Starting with 3-(4'-bromomethyl phenyl)-2-bromobenzofuran, nitrationwith dinitrogen tetraoxide in acetic acid in the presence ofcyclohexene-4-carboxylic acid provides 3-(4'bromomethylphenyl)-2-nitrobenzofuran which is reacted according to the method ofExample 1 with N,N'-dimethylaminoethylamine. The product obtained is3-[4'-(N,N'-dimethylaminoethylaminomethyl)phenyl]-2-nitrobenzofuranhaving the structure ##STR35##

EXAMPLE 29

Using the method of Example 23 and starting with7-hydroxy-2-nitro-3-phenylbenzofuran and N-methylamino ethylchloride,the product obtained isN-methyl-3-(2-nitro-3-phenyl-7-benzofuranyloxy)ethylamine hydrochloridehaving the structure ##STR36##

EXAMPLE 30

Using the method of Example 6, 5-bromomethyl-2-nitro-3-phenylbenzofuranis reacted with piperidine in ethanol to provideN-(2-nitro-3-phenylbenzofuranylmethyl)piperidine having the structure##STR37##

EXAMPLE 31 Step A

A mixture of 4.6 g. (0.02 mole) of 5-cyanomethyl-3-phenylbenzofuran, 1.5g. of sodium azide and 1.2 g. of ammonium chloride in 15 ml. ofN,N-dimethylformaide is heated at 110° C. for 20 hours. The reactionmixture is poured into 200 ml. of water and stirred. The mixture isextracted with 50 ml. of chloroform. The extracts are washed with water,then dried over magnesium sulfate. Evaporation provides a residue whichis recrystallized from ethyl acetate to provide3-phenyl-5-(1H-tetrazol-5yl)methylbenzofuran.

Step B

To a stirred solution of 2.8 g. (0.01 mole) of5-tetrazolylmethyl-3-phenylbenzofuran in 100 ml. of chloroform and 20ml. of dioxane is added dropwise 1.6 g. (0.01 mole) of bromine. After 45minutes the mixture is cooled to 0° C., then the product is separated byfiltration and washed with chloroform. Recrystallization from aqueousethanol provides 2-bromo-3-phenyl-5-(1H-tetrazol-5yl)methylbenzofuranm.p. 215°-217° C.

Step C

To a stirred solution of 1.9 g. (0.005 mole) of2-bromo-3-phenyl-5-tetrazolylmethylbenzofuran in 50 ml. of warm aceticacid and 1 ml. of cyclohexene is added 1 g. of dinitrogen tetraoxide.The mixture is heated on a steam bath for 30 minutes, then cooled to icebath temperature. The product is separated by filtration, washed withacetic acid and diethyl ether and recrystallized from ethanol to provideyellow needles of 2-nitro-3-phenyl-5(1H-tetrazol-5-ylmethyl)benzofuran,m.p. 245°-247° C. having the structure ##STR38##

    ______________________________________    Analysis:         % C       % H    % N    ______________________________________    Calculated for C.sub.16 H.sub.11 N.sub.5 O.sub.3 :                      59.8;     3.1;   21.8    Found:            59.6;     3.5;   21.7.    ______________________________________

EXAMPLE 32

The compounds are tested against the following bacteria:

Streptococcus species

Escherichia coli

The standard plate dilution method for microbial susceptibility toantibiotics is used, employing as a culture medium tryptone soy agar(oxoid) of the following composition:

    ______________________________________    Oxoid tryptone         15    g.    Oxoid soy peptone      5     g.    Sodium chloride        5     g.    Oxoid agar-agar No. 3  15    g.    Water                  1     liter    ______________________________________

The tests may optionally be conducted in the absence or in the presenceof 10 percent horse serum.

In the tests, the selected compound is added to the agar medium to giveconcentrations of zero, 0.1, 1, 10 and 100 milligrams per liter. Seriesof plates with these concentrations are prepared for each compound.Aliquots of broth cultures of each of the species of microorganisms(bacteria) are inoculated onto the agar plates containing the variouscompound concentrations. The plates are incubated at 37° C. in a 10percent carbon dioxide atmosphere for 18 to 24 hours. A microbial growthon each plate is then read visually, and minimal inhibitoryconcentrations are recorded.

The following table shows the results obtained in tests of the compoundsof Examples 1-26 (p indicating partial inhibition at the level specifiedand X indicating inactivity at the highest level tested (100 milligramsper liter)). The following results are obtained in the absence of horseserum.

    ______________________________________                   Microorganism    Compound(1)      Strep.  E.Coli    ______________________________________    1                1       1p    2                10      10    3                1       1p    4                1       1p    5                10      X    6                10      10    7                1       1p    8                10      100p    9                1       100    10               1       10p    11               10      X    12               10p     10p    13               10      100    14               10      1p    15               1       10p    16               10      1p    17               0.1     1    18               1       10    19               10      1    20               1p      100    21               1       1    22               1       1p    23               1       10p    24               10      10    25               10p     1p    26               10      1    ______________________________________     (1)The compounds are designated by the example numbers showing their     preparation herein.

What is claimed is:
 1. A compound of the formula ##STR39## wherein A is BD--,B is an unsubstituted tetrazole ring, D is a carbon-carbon bond or methylene, m and n are zero or one, the sum of m and n is one and X is hydrogen, methyl or ethyl.
 2. A compound according to claim 1 wherein m is one.
 3. A compound according to claim 1 wherein n is one.
 4. A compound of the formula ##STR40## wherein A is BD--,B is an unsubstituted tetrazole ring and D is a carbon-carbon bond or methylene.
 5. A compound of the formula ##STR41## wherein B is an unsubstituted tetrazole ring,D is a carbon-carbon bond or methylene and Z is hydrogen or bromine.
 6. 3-Phenyl-5-(1H-tetrazol-5-yl)benzofuran according to claim
 5. 7. 2-Bromo-3-phenyl-5-(1H-tetrazol-5-yl)benzofuran according to claim
 5. 8. 3-Phenyl-5-(1H-tetrazol-5yl)methylbenzofuran according to claim
 5. 9. 2-Bromo-3-phenyl-5-(1H-tetrazol-5yl)methylbenzofuran according to claim
 5. 10. 2-Nitro-3-phenyl-5(1H-tetrazol-5-yl)benzofuran according to claim
 1. 11. 2-Nitro-3-phenyl-5(1H-tetrazol-5-ylmethyl)benzofuran according to claim
 1. 12. A method for arresting or inhibiting the growth of microorganisms comprising contacting said microorganisms with a compound according to claim 1 in an amount sufficient to inhibit the growth of said microorganisms.
 13. A method for arresting or inhibiting the growth of bacteria comprising contacting said bacteria with a compound according to claim 1 in an amount sufficient to inhibit the growth of said bacteria.
 14. An antimicrobial composition comprising an antimicrobially effective amount of a compound according to claim 1 dispersed in a pharmaceutically acceptable extending medium.
 15. An antibacterial composition comprising an antibacterially effective amount of a compound according to claim 1 dispersed in a pharmaceutically acceptable extending medium. 